Fabian Nicieza does this a lot, too, to the point that I couldn't really enjoy his work on THUNDERBOLTS. Figuring out some of the mysteries in the book seemed to depend a lot on having read every minor title Nicieza ever wrote. And, as much of a geek as I am, my depth of knowledge wasn't sufficient to have a shot at guessing the answers to long-running questions.

Funny you should mention Fabes, David. I have an interview with him where he says that, in his early days at Marvel, when he was doing filler stories, backups, and eight-pagers for Marvel Comics Presents, he tied a lot of those stories together via a villain character called The Bengal. If you bother to track down Bengal's appearances during that time and read them in chronological order, they form a multi-part Bengal series of sorts, culminating in a three-parter during the early days of New Warriors.

While I love him anyway, Peter David is clearly guilty of nepotistic continuity. Take Spider-Man 2099, where PAD pulled the New Universe Justice (whom David worked on) into 2099, along with a mysterious villain eventually revealed to be Rick Jones. Naturally, the revelation took place not in Spider-Man 2099, but in Captain Marvel about eight years later. The Maestro showed in that story arc as well.

Or how Fallen Angel? Sure, Lee is meant to be Linda Danvers, conplete with veiled references to the time she got knocked up by Pre-Crisis Superman, but he also had Sachs and Violens show up. They're characters from PAD's Marvel Epic miniseries in the 80's. Sachs turned out to the sister of the local Bete Noir madame.